PRESIDENTIAL ADDRESS. 325 



fine Sea Island cotton. To enable the cotton industry to be established in the 

 west Indies it wae necessary from the first to ascertain the best type of cotton 

 to grow lu each Island, how to plant and cultivate it, how to protect it from 

 insect and fungus trouble, and liow to maintain or improve the quality and 

 quantity, of the lint produced. The results so far obtained may be realisetl from 

 tne fact that tlie value of the exports of Sea Island cotton from the West Indies 

 in recent years has reached a total of two million sterling. The general conditions 

 in the West Indian islands owing to their small size and comparative isolation 

 should enable them to maintain a high purity of cotton. In Egypt and other 

 cotton-growing countries with continuous areas contamination by natural crossing 

 leads to rapid deterioration of pure strains so that a system of continued seed 

 renewal is necessary. Harland, whose services in the West Indies have been 

 provided by. a grant from the Imperial Department of Scientific and Industrial 

 Research, has in hand important investigations with the view of placing the 

 work of cotton selection and breeding on scientific lines. 



He has shown that the yield of lint per acre depends on a number of factors 

 of a morphological and physiological character. In a general way it may be said 

 that the yield is dependent on the climatic conditions, so an effort is being made 

 to produce varieties which will interact with the environment conditions to the 

 best advantage. Although Harland 's work so far is of a preliminary character, 

 he is able to suggest the conclusion that, following certain lines of selection and 

 breeding, and bearing in mind the relative importance of lint index and lint 

 percentage, it is possible to isolate a strain of Sea Island cotton with a weight 

 of lint per boll 31 per cent, greater than that of the ordinary sorts in cultivation. 



Considerable losses occur in some seasons from the attacks of insect and 

 fungous pests. In some instance the Internal Boll disease is very destructive. 

 This is due to the puncture of the young bolls by cotton stainers (Dysdercns) and 

 green bug {Nezara) and the infection of the punctured locks or bolls by certain 

 specific fungi which cause either total loss or the staining of the lint, accoixling 

 to the amount and time of infection. 



The green bug is naturaly controlled by egg parasites, but the cotton stainers 

 are subject to little or no control. In St. Vincent highly successful results 

 have followed the systematic cutting out, over the whole island, of two species 

 of trees (Seaside Mahoe and the Silk cotton) on the fruits of which the cotton 

 stainers breed during the period between the cotton crops. The investigation 

 of the Internal Boll disease has entailed wide research, and illustrates the great 

 complexity of problems in tropical plant pathology, as also the need of correla- 

 tion and the combination of knowledge obtained by simultaneous action from 

 several points of view. 



A point of scientific interest is the inheritance of immunity in cotton from 

 the attacks of the Leaf-blister mite (Eriophyes gossypii). Harland believes he 

 has obtained this by crossing an immime type of native cotton with a susceptible 

 type of Southern Cross Upland cotton. In the F/3 generation all the plants 

 breed true to immunity.- This is important from an economic point of view, 

 for it may lead to the possibility of the production of an immune strain of Sea 

 Island cotton vvhich has hitherto been very badly attacked by the Leaf -blister 

 mite. Another instance of immunity from insect attack is a hybrid of maize 

 (Zea indentata) and Teosii}tp_ mexicana, which is claimed to be totally immune 

 to the attacks of certain aphTds.^ 



As already mentioned, India is the second largest producer of cotton. In 

 1906-7 it was estimated that there were about 20 million acres under cotton, 

 with a production of nearly 5 million bales. It is unfortunate that the quality 

 of East Indian cotton is not high in spite of the considerable efforts made in 

 recent years to improve it. 



Cambodia cotton for a time proved successful in Southern India, and has 

 lately been introduced to Madras, but chief attention is directed to the im- 

 provement by systematic selection of pure strains adapted to local conditions. 

 In ;\[adras in 1917-18 there were 2.50,000 acres under new varieties of cotton, 

 yielding increased returns to the rayats of the value of £416,000 per annum. 

 A variety known as ' roseum ' was planted in the Central Provinces in 1916-17 on 



2 West Ind. Bull, xvii., 162. 

 ' Rev. App. Entom. Ser. A., vi.. 29. 

 1919. " c c 



